JPH0723680B2 - Tunnel shield digging method - Google Patents

Description

FIELD OF THE INVENTION The present invention supports the extension surface by means of a pressure medium which, via the controlled gap of the shield, shields the tail or the ground or rock and the tunnel support. Is connected to the interstitial space between them, and the interstitial space is closed towards the working space between the shield tail and the tunnel support, and in the interstitial sealing ring the press concrete is interspersed by the pipe pieces. The present invention relates to a shield excavation method for a tunnel by a shield excavator having a work space that is pushed into the interior thereof and receives an external pressure. This method is used especially on loose ground. The pressure medium is a fluid medium. For example, water, thixotropic liquids, or gases, especially air, can be used. The pressed concrete may contain any binder, especially an underwater curing binder or a synthetic resin binder. The gap sealing ring can be made in various ways.

Prior Art When working in the manner described at the outset, the non-sealing seam between the gap sealing ring and the shield tail and / or the tunnel support cannot always be eliminated. This is especially true if the tunnel support is constructed as a tubular support made by assembling tubular segments and it is not possible to prevent the individual tubular segments from being slightly displaced from each other in the radial direction. To elaborate, we have found the following for this problem area:

Especially when tunneling in loose ground,
It is supported mechanically by the exploration disk or by a pressure medium. Mechanical support is imperfect and causes deformation of the extension surface, which causes subsidence of the terrain surface. The support of the extension surface by the liquid is extremely effective and produces excavation with less displacement. It is disadvantageous that the drilling material must be mixed with the liquid and pumped. This drilling material is separated from the liquid outside the mine, which means that
Especially in the case of fine ground, it takes time. On the other hand, it is advantageous for supporting compressed air. This is because the mined ground can be dried and sent out. Actually, compressed air has been added to the entire tunnel pipe to actually support the ground on the extension surface. Attempts to add compressed air only to the working space in the front part of the shield and allow it to work at ambient pressure have been well known but have been unsuccessful. If the pressure medium flows backwards in the control gap outside the shield and enters the working space due to the incomplete sealing of the gap sealing ring, pressure medium losses and especially compressed air losses occur. This interstitial space with a gap width of approximately 10 cm is compressed by the press concrete at the same time as the shield feed as described above, so that the surrounding ground, which may be in groundwater, does not enter into the interstitial space. . However, it cannot be guaranteed that the pressing pressure for pressed concrete is always greater than the pressure generated by the load. This causes the concrete to fall into the gap, which makes it impossible to completely fill the shield tail gap. Similar conditions occur in brittle rocks.

A pressure medium, in particular a gaseous pressure medium, can flow through the incompletely filled interstitial space, which gaseous pressure medium flows through the control gap surrounding the shield to the rear of the shield tail. If the gap sealing ring is not closed, the pressure medium escapes into the working space. Incomplete filling of the interstitial space can be prevented by a movable elastically supported interstitial sealing ring (German Patent Application No. 3642).
893.0-24 specification). But even with this
For example, in the case of a tubular support, if a gap occurs between adjacent segments for some reason, and the packing of the gap sealing ring slides over this gap, the gap space cannot be reliably filled. Occasionally unsealed seams of 15 mm or less occur. Through this non-sealing seam, the liquid press concrete flows out into the interior of the shield, whereupon the pressure considered in the press concrete cannot be maintained because it supports the surrounding ground. The risk of this outflow is greater at higher pressing pressures, which is necessary when the tunnel is deep.

OBJECT OF THE INVENTION The object of the invention is to provide a gap sealing ring and a shield tail and / or
Another object is to improve the method as described at the outset such that the non-sealing seam that may occur between the tunnel bearings is automatically closed, thus avoiding the disadvantages mentioned above.

Structure of the Invention In order to solve this problem, the present invention shows the following. (A) A tunnel machine is propelled through an underground structure to form an excavation hole, and (b) a tunnel support is arranged in the excavation hole with a gap with respect to the hole wall, in which case the tunnel described above. The excavator has a shield tail, the shield tail contacts the hole wall, and surrounds the tunnel support with a gap from the support, (c) the shield tail and the tunnel support. By providing a gap sealing ring therebetween, the gap space is closed in the excavation direction of the tunnel machine, and (d) the gap sealing ring is elastically supported by fluid pressure, and the fluid pressure causes the gap sealing ring to (E) Concrete is press-fitted into the gap space formed between the tunnel support and the hole wall at high pressure, and (f) Press-fitted into the gap space. Ko The pressure of the cleat pushes the gap sealing ring in the above direction against the fluid pressure, and (g) (g1) includes coarse aggregate having a particle size of 4 mm or more in the concrete. , A particle filter composed of a layer of coarse-grained aggregate is formed in front of the non-sealing seam generated between the gap sealing ring and the tunnel support, and (g2) in the concrete press-fitted into the gap space. To contain fine aggregates composed of sand and / or fibers so that the fine aggregates are trapped in the above-mentioned particle filter, and (g3) a particle filter capturing the above-mentioned fine-grain aggregates is formed. Sealing the non-sealing seam by pushing the concrete towards the non-sealing seam so that the fine-grained aggregate that is trapped in the particle filter seals the non-sealing seam. But Other accordance connexion is constructed in an existing teaching, and flow agents, it is clear that contain other conventional additives such as retarders and stabilizers. Particulate filters are created for hydrodynamic reasons before the non-sealing seam and during and after that clogging.

When using pressed concrete in which the particle size of the coarse-grained aggregate is greater than or equal to 4 mm, the above-mentioned particle filtering action is always achieved. This is especially achieved when using pressed concrete in which the fine aggregate is sand and / or fibers. The procedure described above is particularly important when using the elastically supported gap sealing ring as described above, which is pushed towards the pressed concrete in the gap space. The combination of the use of a gap-sealing ring arranged and formed in this way with the method procedure is therefore of particular importance. The sealing possible through the formation of a particle filter is surprisingly effective even when pressing concrete into the interstitial space with a pressure below 10 bar.

Embodiment An embodiment of the present invention will be described in detail below with reference to the drawings.

The illustrated gap sealing ring is arranged between the rear end of the shield tail 1 and the front end of the tunnel support 2 and is used to seal the gap space 3 during the pressing of the gap space with press concrete. . The gap sealing ring is supported freely movable relative to the shield tail 1 and the tunnel support 2 and elastically in the direction of excavation via an adjustable support unit in the form of a cylinder piston arrangement, for example a shield. ing. These support units are not shown in detail in the drawing, only one of the mounting holes 4 for mounting the support unit is shown in FIG. A plurality of press material supply pipe pieces 5 are provided on the front end surface of the gap sealing ring so as to be uniformly dispersed over the circumference (see FIG. 2). Furthermore, the gap sealing ring has an elastic outer packing 6 and an elastic inner packing 7. The elastic outer packing 6 consists of a rubber or plastic ring which can contact the inside of the shield tail 1. For this purpose, a radial adjusting screw 8 is provided accordingly. The inner packing 7 which can be pressed onto the outside of the tunnel support 2 consists of a compliant spring packing which is attached to the gap sealing ring by means of radial screws 9.

As shown diagrammatically in FIGS. 1 and 2, the unsealed seam 10 is formed by the displacement of the segments in the tunnel support 2 in the region where the cross-sections are open. As shown in FIG. 1, a particle filter 11 consisting of a layer of coarse-grained crushed stone of pressed concrete, that is, a coarse-grain aggregate, is formed before the non-sealed seam 10, and the hole of the particle filter has a coarse-grain aggregate. Closed by 12. Some of them pass through the particle filter and close the unsealed seam 10. The proportion of coarse-grained aggregate, especially the proportion of powder particle components, can be higher than that of ordinary press concrete. The advantageous configuration of the present invention has the following features. That is, to the press concrete, precipitated silicic acid or amorphous silicic acid in the form of silicic acid produced by high temperature hydrolysis is added. In general, 2 to 4% by weight of amorphous silicic acid, based on the weight of cement, is sufficient.
The matching of other additives such as flow agents, retarders and stabilizers can also provide improved tightness. It is also within the scope of the invention to add bentonite in an amount of, for example, 2 to 6% by weight, preferably 4% by weight, based on the weight of the cement.

[Brief description of drawings]

FIG. 1 is a sectional view of the gap sealing ring when tunneling is performed by the method according to the present invention, and FIG. 2 is a sectional view corresponding to FIG. 1 of the gap sealing ring at another angular position. 1 ... Shield tail, 2 ... Tabbing support, 3 ... Gap space, 4 ... Mounting hole, 5 ... Press material supply pipe piece, 6
...... Outer packing, 7 …… Inner packing, 8 …… Adjusting screw, 9 …… Radial screw, 10 …… Unsealed seam, 11 ……
Particle filter, 12 ... Additive

Claims (3)

[Claims] 1. A shield excavation method for a tunnel, comprising: (a) propelling a tunnel excavator through an underground structure to form an excavation hole; and (b) forming a gap in the excavation hole with respect to a hole wall. The tunnel support (2) is arranged so that the tunnel excavator has a shield tail (1), the shield tail contacts the hole wall, and the tunnel support is removed from the support. (C) The gap space (3) is closed in the excavation direction of the tunnel machine by providing a gap sealing ring between the shield tail and the tunnel support, and (d) The gap sealing ring is elastically supported by a fluid pressure, and the fluid pressure gives a resistance force to the advance of the gap sealing ring in the direction, and (e) concrete is provided between the tunnel support and the hole wall. Formation (F) The pressure of the concrete press-fitted into the gap space (3) pushes the gap sealing ring in the above direction against the fluid pressure, and ) (G1) The concrete contains a coarse aggregate (11) with a particle size of 4 mm or more, and this coarse aggregate is not sealed between the gap sealing ring and the tunnel support (2). In the front of the seam (10), a particle filter composed of a layer of coarse-grained aggregate is formed, and (g2) fine particles composed of sand and / or fibers in concrete which is press-fitted into the gap space (3). Including aggregate (12),
This fine-grain aggregate is made to be trapped in the particle filter, and (g3) the fine-grain aggregate in which the fine-grain aggregate (12) is trapped is formed and the fine-grain bone trapped in the particle filter is formed. A tunnel characterized by sealing the unsealed seam (10) by pushing concrete towards the unsealed seam so that the material seals the unsealed seam (10). Shield digging method. 2. The proportion of fine aggregates is higher than the standard proportion of fine aggregates in common concrete.
The method described in. 3. The method according to claim 1, wherein precipitated silicic acid or silicic acid in the form of silicic acid made by high temperature hydrolysis is mixed with concrete.